This invention relates to roller curtains. More particularly, it pertains to an improved method of insulating a roller curtain which includes several curtain slats, each slat consisting of an outer skin and an inner skin that are fit together at their edges and surround an insulating inner core.
The use of roller curtains in such items as roll-up doors is well known. Frequently, roller curtains are used in the entrance ways of warehouses and factories. When the curtain is in the rolled-down position, it blocks the entryway. Because the roller curtain is made of several slats connected together by joints, the roller curtain can be rolled up into a coil, usually on the top of the entryway.
Roller curtains are often used on exterior entryways. In this case, the outside portion of the curtain may be exposed to harsh weather conditions. For this reason, the slats are commonly made of two connected skins. The outside skin is generally made of metal to protect the curtain from the exterior weather conditions. Where the difference between the inside and outside temperatures are significant, however, the inner skin of the slats are not made of metal. Instead, the inner skin is made of a material that is resistant to heat transfer so that the heat on one side of the curtain is not transferred to the other side. Also, this permits a lighter material than metal to be used, which reduces the weight of the curtain. To further protect against heat transfer, it is common in the art to fill the space between the inner and outer skins with insulation. A problem area remains, however, where the slats are connected to one another.
In heat insulated roller curtains, as they are used for example with roll-up doors, the joint area between the various roller slats is a common source of heat dissipation. The joint connecting neighboring slats may have the metal outer skin of one slat hinged on the metal outer skin of a neighboring slat. In this case, the inside air is exposed to the metal skin which either directly contacts the outside air, or contacts another metal skin which contacts the outside air. Compounding the problem is the fact that the joints are not airtight. Thus, at certain pressure differences between the inside and outside air, an air flow is created which results in heat transfer. A lack of insulation in the joint area between the slats can result in a substantial amount of heat transfer, especially with large area roller curtains or where there is a high temperature difference between the sides of the curtain.